Como altero o texto das legendas existentes?
If you want to change some of the text in the captions, you need to modify the fields used to create the captions. (Automatic captions are implemented through the use of fields in the document.)
You can change the text in the fields by first displaying the field codes in your document (press Shift+F9). You should be able to see what the field codes look like for your captions; examine one to see how it is constructed, looking specifically for the text you want to change.
Next press Ctrl+H to display the Replace tab of the Find and Replace dialog box. Use the controls in the dialog box to specify the caption text you want to change (from within the field you examined) and what you want the text to be. You can then use the controls to step through all the occurrences of the text and change it, as desired.
There are other things you can change in the fields using this same technique. For instance, you may want to change the numbering of your captions from Arabic to Roman. If you examine the field code used for a caption, it may appear similar to this:
{Seq Figure *\ arabic}
You can easily use the Find and Replace method to change the word "arabic" to "roman." When you are done making the changes, press Alt+F9 to change the field codes back to their results.